U.S. patent application number 09/949647 was filed with the patent office on 2003-03-13 for material mixing device and method.
This patent application is currently assigned to TAH Industries Inc.. Invention is credited to Henning, Jason, Horner, Terry A..
Application Number | 20030048694 09/949647 |
Document ID | / |
Family ID | 25489366 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030048694 |
Kind Code |
A1 |
Horner, Terry A. ; et
al. |
March 13, 2003 |
Material mixing device and method
Abstract
A static mixer for mixing at least two materials wherein the
mixer includes a conduit having interior walls and a central,
longitudinal axis along which materials flow. The mixer has a
number of baffles arranged inside the conduit and each baffle has
at least two, planar webs that intersect one another and extend
parallel to the flow direction wherein one web forms a rear fin
extending in the material flow direction. In addition, the mixer
has at least two, forward angled surfaces and at least two, rear
angled surfaces that are connected by the two planar webs.
Inventors: |
Horner, Terry A.;
(Allentown, NJ) ; Henning, Jason; (Plainsboro,
NJ) |
Correspondence
Address: |
PATENT ADMINSTRATOR
KATTEN MUCHIN ZAVIS ROSENMAN
525 WEST MONROE STREET
SUITE 1600
CHICAGO
IL
60661-3693
US
|
Assignee: |
TAH Industries Inc.
|
Family ID: |
25489366 |
Appl. No.: |
09/949647 |
Filed: |
September 12, 2001 |
Current U.S.
Class: |
366/337 |
Current CPC
Class: |
B01F 25/43151 20220101;
B05C 17/00516 20130101; B01F 25/4321 20220101 |
Class at
Publication: |
366/337 |
International
Class: |
B01F 005/06 |
Claims
What is claimed is:
1. A static mixer for mixing at least two materials comprising: a
conduit having interior walls and a central, longitudinal axis
wherein said conduit passes the materials in a flow direction along
said longitudinal axis; a plurality of baffles arranged inside said
conduit, each baffle having a first and second forward, angled
surface and a first and second rear, angled surface, said forward
surfaces are connected by a first generally planar web that extends
parallel to the flow direction, and said rear angled surfaces are
connected by a second, generally, planar web that extends parallel
to the flow direction said webs intersect one another and said
second web extends past said rear angled surfaces to form a fin
extending in the flow direction.
2. The static mixer according to claim 1, further comprising a
plurality of supplemental baffles arranged inside said conduit,
each baffle having six forward angled surfaces and six rear, angled
surfaces connected by four generally planar webs, wherein said webs
extend generally parallel to the flow direction and intersect each
other and at least one planar web extends beyond said rear, angled
surfaces to form a fin extending in the material flow
direction.
3. The static mixer according to claim 2, wherein said supplemental
baffles provide radial movement of material flow.
4. The static mixer according to claim 2, having a total of
eighteen baffles wherein at least two of the eighteen baffles are
supplemental baffles.
5. The static mixer according to claim 2, having a total of
twenty-four baffles wherein at least two of the twenty-four baffles
are supplemental baffles.
6. The static mixer according to claim 2, having a total of
thirty-six baffles wherein at least four of the thirty-six baffles
are supplemental baffles.
7. The static mixer according to claim 1, wherein said angled
surfaces each comprise an non-planar, curved surface.
8. The static mixer according to claim 1, further comprising a pair
of opposed side walls integral with said baffles and fit within
opposed interior walls of said conduit.
9. A static mixer for mixing at least two materials comprising: a
conduit having interior walls and a central, longitudinal axis
wherein said conduit passes the materials in a flow direction in
the direction of said longitudinal axis; a plurality of baffles
arranged inside said conduit, each baffle comprising a first,
generally planar web having opposing sides and a second, generally
planar web having opposing sides, wherein said webs extend
generally parallel to the flow direction and intersect each other;
a first, forward surface perpendicular to one side of said first
web and at an angle a plane perpendicular to the longitudinal axis;
a second, forward surface perpendicular to the other said side of
said first web and at an angle to the plane perpendicular to the
longitudinal axis; a first, rear surface perpendicular to one side
of said second, planar web and at an angle to the plane
perpendicular to the longitudinal axis; and a second, rear surface
perpendicular to the other said side of said second web and at an
angle to the plane perpendicular to the longitudinal axis, wherein
at least one planar web extends past the first and second rear
surfaces in the flow direction to form a rear fin.
10. The static mixer according to claim 9, further comprising a
plurality of supplemental baffles arranged inside said conduit,
each baffle comprising: a first, generally planar web having
opposing sides and a second generally planar web having opposing
sides wherein said webs extend generally parallel to the flow
direction and intersect each other; a first, forward surface
perpendicular to one side of said first web and at an angle to the
plane perpendicular to the longitudinal axis; a second, forward
surface perpendicular to said other side of said first web and at
an angle to the plane perpendicular to the longitudinal axis; a
first, rear surface perpendicular to one side of said second,
planar web and at an angle to the plane perpendicular to the
longitudinal axis; a second, rear surface perpendicular to said
other side of said second web and at an angle to the plane
perpendicular to the longitudinal axis; a third, generally planar
web having opposing sides wherein said web extends generally
parallel to the flow direction and intersects said second planar
web; a third, forward, surface perpendicular to one side of said
second web and at an angle to the plane perpendicular to the
longitudinal axis; a fourth, forward surface perpendicular to said
other side of said second web and at an angle to the plane
perpendicular to the longitudinal axis; a fifth, forward surface
perpendicular to one side of said third web and at an angle to the
plane perpendicular to the longitudinal axis; a sixth, forward
surface perpendicular to said other side of said third web and at
an angle to the plane perpendicular to the longitudinal axis; a
fourth generally planar web having opposing sides wherein said web
intersects said third planar web and extends generally parallel to
the flow direction; a third, rear surface perpendicular to one side
of said third, planar web and at an angle to the plane
perpendicular to the longitudinal axis; a fourth, rear surface
perpendicular to the other said side third web and at an angle to
the plane perpendicular to the longitudinal axis; a fifth, rear
surface perpendicular to one side of said fourth, planar web and at
an angle to the plane perpendicular to the longitudinal axis; and a
sixth, rear surface wherein said surface is perpendicular to said
other side of said fourth web and at an angle to the material
flow.
11. The static mixer according to claim 10, wherein said
supplemental baffles provide radial movement of material flow.
12. The static mixer according to claim 10, having a total of
eighteen baffles wherein at least two of the eighteen baffles are
supplemental baffles.
13. The static mixer according to claim 10, having a total of
twenty-four baffles wherein at least two of the twenty-four baffles
are supplemental baffles.
14. The static mixer according to claim 10, having a total of
thirty-six baffles wherein at least four of the thirty-six baffles
are supplemental baffles.
15. The static mixer according to claim 9, wherein said forward and
rear surfaces each comprise a non-planar, curved surface.
16. The static mixer according to claim 9, further comprising a
pair of opposed side walls integral with said baffles and fit
within opposed interior walls of said conduit.
17. A static mixer for mixing at least two materials comprising: a
conduit having interior walls and a central, longitudinal axis
wherein said conduit passes the materials in a flow direction along
said longitudinal axis; a plurality of baffles arranged inside said
conduit, each baffle having a first and second forward, angled
surface and a first and second rear, angled surface, said forward
surfaces are connected by a first generally planar web that extends
parallel to the flow direction, and said rear angled surfaces are
connected by a second, generally, planar web that extends parallel
to the flow direction said webs intersect one another, said baffles
each having a leading edge and a trailing and a length to width
ratio of 0.4 to 0.7 wherein the length is the distance between the
leading edge and the trailing edge and the width is the shortest
diameter of said conduit perpendicular to said flow direction and
passing through said central, longitudinal axis of said conduit and
defined by the shortest distance between two opposing, interior
walls of said conduit.
18. The static mixer according to claim 18, further comprising a
plurality of supplemental baffles arranged inside said conduit,
each baffle having six forward angled surfaces and six rear, angled
surfaces connected by four generally planar webs, wherein said webs
extend generally parallel to the flow direction and intersect each
other, said baffles each having a leading edge and a trailing edge
at an angle to one another and said baffles having a length to
width ratio of 1.0 to 1.6 wherein the length is the distance
between the leading edge and the trailing edge and the width is the
shortest diameter of said conduit perpendicular to said flow
direction and passing through said central, longitudinal axis of
said conduit and defined by the shortest distance between two
opposing, interior walls of said conduit.
19. The static mixer according to claim 17, wherein said angled
surfaces each comprise an non-planar, curved surface.
20. The static mixer according to claim 17, further comprising a
pair of opposed side walls integral with said baffles and fit
within opposed interior walls of said conduit.
21. A static mixer for mixing at least two materials comprising: a
conduit having interior walls and a central, longitudinal axis
wherein said conduit passes the materials in a flow direction along
said longitudinal axis; a plurality of baffles arranged inside said
conduit, each baffle comprising a first, generally planar web
having opposing sides and a second, generally planar web having
opposing sides, wherein said webs extend generally parallel to the
flow direction and intersect each other; a first, forward surface
perpendicular to one side of said first web and at an angle to the
plane perpendicular to the longitudinal axis; a second, forward
surface perpendicular to the other side of said first web and at an
angle to the plane perpendicular to the longitudinal axis; a first,
rear surface is perpendicular to one side of said second, planar
web and at an angle to the plane perpendicular to the longitudinal
axis; and a second, rear surface perpendicular to the other side of
said second web and at an angle to the plane perpendicular to the
longitudinal axis; and said baffles each having a leading edge and
a trailing edge at an angle to one another and said baffles having
a length to width ratio of 0.4 to 0.6 wherein the length is the
distance between the leading edge and the trailing edge and the
width is the shortest diameter of said conduit perpendicular to
said flow direction and passing through said central, longitudinal
axis of said conduit and defined by the shortest distance between
two opposing, interior walls of said conduit.
22. The static mixer according to claim 21, further comprising a
plurality of supplemental baffles arranged inside said conduit,
each baffle comprising: a first, generally planar web having
opposing sides and a second generally planar web having opposing
sides wherein said webs extend generally parallel to the flow
direction and intersect each other; a first, forward surface
perpendicular to one side of said first web and at an angle to the
plane perpendicular to the longitudinal axis; a second, forward
surface perpendicular to said other side of said first web and at
an angle to the plane perpendicular to the longitudinal axis; a
first, rear surface perpendicular to one side of said second,
planar web and at an angle to the plane perpendicular to the
longitudinal axis; a second, rear surface perpendicular to said
other side of said second web and at an angle to the plane
perpendicular to the longitudinal axis; a third, generally planar
web having opposing sides wherein said web extends generally
parallel to the flow direction and intersects said second planar
web; a third, forward, surface perpendicular to one side of said
second web and at an angle to the plane perpendicular to the
longitudinal axis; a fourth, forward surface perpendicular to said
other side of said second web and at an angle to the plane
perpendicular to the longitudinal axis; a fifth, forward surface
perpendicular to one side of said third web and at an angle to the
plane perpendicular to the longitudinal axis; a sixth, forward
surface perpendicular to said other side of said third web and at
an angle to the plane perpendicular to the longitudinal axis; a
fourth generally planar web having opposing sides wherein said web
intersects said third planar web and extends generally parallel to
the flow direction to form a fin extending in the flow direction; a
third, rear surface perpendicular to one side of said third, planar
web and at an angle to the plane perpendicular to the longitudinal
axis; a fourth, rear surface perpendicular to said other side of
said third web and at an angle to the plane perpendicular to the
longitudinal axis; a fifth, rear surface perpendicular to one side
of said fourth, planar web and at an angle to the plane
perpendicular to the longitudinal axis; and a sixth, rear surface
perpendicular to said other side of said fourth web and at an angle
to the plane perpendicular to the longitudinal axis; and said
supplemental baffles having a leading edge and trailing edge
perpendicular to one another and said baffles having a length to
width ratio of 1.0 to 1.4 wherein the length is the distance
between the leading edge and the trailing edge and the width is the
shortest diameter of said conduit perpendicular to said flow
direction and passing through said central, longitudinal axis of
said conduit and defined by the shortest distance between two
opposing, interior walls of said conduit.
23. The static mixer according to claim 21, wherein said forward
and rear surfaces each comprise a non-planar, curved surface.
24. The static mixer according to claim 21, further comprising a
pair of opposed side walls integral with said baffles and fit
within opposed interior walls of said conduit.
25. A static mixer for mixing at least two materials comprising: a
conduit having interior walls and a central, longitudinal axis
wherein said conduit passes the materials in a flow direction along
said longitudinal axis; and a plurality of baffles arranged in said
conduit, each baffle having at least two forward surfaces and at
least two rear surfaces connected by at least two planar webs,
wherein said webs are arranged at varying distances from the
interior walls of said conduit, wherein the interior walls and said
webs combine to form two, asymmetrical, lateral passageways
extending in said flow direction, each passageway having a varying
flow area.
26. The static mixer according to claim 25, wherein one of said
webs extends past said rear surface to form a fin extending in the
flow direction.
27. A static mixer according to claim 26, further comprising a
plurality of supplemental baffles arranged inside said conduit,
each baffle having six forward angled surfaces and six rear, angled
surfaces connected by four generally planar webs, wherein said webs
extend generally parallel to the flow direction and intersect each
other and at least one planar web extends beyond said rear, angled
surfaces to form a fin extending in the material flow
direction.
28. The static mixer according to claim 27, wherein said
supplemental baffles provide radial movement of material flow.
29. The static mixer according to claim 27, having a total of
eighteen baffles wherein at least two of the eighteen baffles are
supplemental baffles.
30. The static mixer according to claim 27, having a total of
twenty-four baffles wherein at least two of the twenty-four baffles
are supplemental baffles.
31. The static mixer according to claim 27, having a total of
thirty-six baffles wherein at least four of the thirty-six baffles
are supplemental baffles.
32. The static mixer according to claim 25, wherein said forward
and rear surfaces each comprise a non-planar, curved surface.
33. The static mixer according to claim 25, further comprising a
pair of opposed side walls integral with said baffles and fit
within opposed interior walls of said conduit.
34. A method for mixing at least two materials comprising the steps
of: injecting a stream of materials into said conduit; dividing
said stream into a plurality of parts by urging the stream past
baffles having a length to width ratio of 0.4 to 0.7 wherein the
length is the distance between a leading edge of a baffle and the
trailing edge of the baffle and the width is the shortest diameter
of said conduit perpendicular to said flow direction and passing
through said central, longitudinal axis of said conduit and defined
by the shortest distance between two opposing, interior walls of
said conduit; and recombining said parts in an overlapping
relationship.
35. The method according to claim 24, further comprising the steps
of: recombining said parts with a outer portion of the original
stream displaced toward the geometrical center of said stream.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to a material mixing
device and method. More particularly, the present invention relates
to a device and method for mixing materials such as, e.g., high
viscosity liquids.
BACKGROUND OF THE INVENTION
[0002] Various methods, machines and devices have been utilized for
mixing liquids, liquid suspensions and fluids of high or differing
viscosity. Most are based upon the use of a mechanically driven
agitator or stirrer operating in the material to be mixed, whereby
shear will promote the thorough and homogeneous intermixing of the
liquids. Methods utilizing a normal rotational shear mixing
process, particularly when applied to high viscosity liquids, are
sometimes inefficient and non-desirable. In such cases, a large
quantity of power is required to drive the agitating or mixing
devices and much of the power is unavoidably converted into heat.
In addition, the creation of turbulence, which is typical of a
normal rotational mixing process, is neither desirable nor
practicable in the mixing of materials of high or differing
viscosities. The energy transformed into heat usually contributes
little, if anything, to the mixing process. In many cases, the heat
must be removed to avoid overheating of the mixture and such heat
is almost always wasted, especially when conventional cooling means
are used to absorb it.
[0003] Often, apparatuses employed in the manipulation of viscous
materials are physically very large and costly to maintain and
operate. Frequently, the characteristics of highly viscous
materials are such that in order to promote thorough and homogenous
intermixing, high rates of shear must be utilized, requiring the
use of close mechanical clearances. Thus, viscous materials are
oftentimes mixed on rolls, mills and/or rotary pumps.
Alternatively, viscous fluids and mixtures have been mixed by
forcing them to flow through passageways designed to cause
turbulence in the flowing stream. The aforementioned passageways
produce turbulence by a displacement of the stream elements as they
are separated and recombined during the flow; however, the fluids
tend to stay in a laminar flow state.
[0004] It has been found that it is beneficial to mix the fluids
while they remain in a laminar flow state. This is accomplished by
"static mixers." Instead of causing random turbulent flow to
disperse the fluid, static mixers cause a successive geometric
layering effect. In this way, the number of layers increases while
the thickness of each layer decreases as the fluids are pushed
through the mixer. At the outlet of the mixer, the layers are thin
enough such that the fluid components will diffuse through each
other's layers, resulting in a fully homogeneous mix. This mix
method is largely independent of fluid speed, and therefore
requires relatively little energy input to drive the mixing. It's a
smooth, simple, organized and relatively effortless method for
producing a mix.
[0005] Despite their advantages, static mixers present in the art
do have drawbacks. If the fluids are of different viscosities,
there is a tendency for the low viscosity fluid to channel along
the outside wall of the mixer and not be properly included in the
layering process. In addition, due to the high viscosity of the
materials being mixed, use of such mixers as described above can be
messy and require the use of expensive solvents to clean the mixers
between uses. Therefore, low cost, disposable mixers are preferred.
However, if the mixers are disposed between uses, valuable material
product retained within the mixer may be wasted.
[0006] Ideally, the materials to be mixed should be injected into
the mixer stoichoimetrically and metered as a function of time.
However, several factors may contribute to uneven proportions of
injected material. For example, when using materials of differing
viscosity, pulsations in the supply pump may cause uneven
distribution of material entering the mixer. Also, in cases where
small amounts of material are dispensed in succession, pre-flow and
after-flow "drool" of the lower viscosity fluid may favor more of
that component to enter the mixer, affecting the chemical diffusion
of the materials and/or the homogeneous mixing of the
materials.
[0007] Accordingly, it is desirable to provide a low cost,
disposable mixer that allows the mixing of high viscosity liquids
without the production of heat and/or turbulence associated with a
mechanically driven agitator or stirrer while expending minimal
energy. Similarly, there is a need for a low cost, disposable mixer
that retains minimal material product after use and that is short
in length, providing maximum control over the product's
application. Additionally, there is a need for a mixer that
provides a correcting factor to compensate for uneven distribution
of material injected into the mixer.
SUMMARY OF THE INVENTION
[0008] The foregoing needs are met, at least to a great extent, by
the present invention where, in one aspect, a static mixer for
mixing at least two materials includes a conduit having interior
walls and a central, longitudinal axis along which the materials
flow. The mixer has a number of baffles arranged inside the conduit
and each baffle has two planar webs that intersect one another and
extend parallel to the flow direction. In addition, the mixer has
two, forward angled surfaces and two, rear angled surfaces that are
connected by the two planar webs.
[0009] In another aspect, the invention provides a static mixer for
mixing at least two materials that includes a conduit having
interior walls and a central, longitudinal axis along which the
materials flow. The mixer has a number of baffles arranged inside
the conduit and each baffle has two planar webs that intersect one
another and extend parallel to the flow direction wherein one web
extends to form a rear fin extending in the material flow
direction. In addition, the mixer has two forward angled surfaces
and two rear angled surfaces that are connected by the two planar
webs. Each individual baffle has a leading edge and trailing edge
and a length to width ratio of 0.4 to 0.7. The length is the
distance between the leading edge and the trailing edge. The width
is the shortest internal diameter of the conduit taken
perpendicular to the flow direction and passing through the
central, longitudinal axis of the conduit.
[0010] In yet another aspect, the invention provides a static mixer
for mixing at least two materials that includes a conduit having
interior walls and a central, longitudinal axis along which
materials flow. The mixer has a number of baffles arranged inside
the conduit and each baffle has at least two planar webs that
intersect one another and extend parallel to the flow direction
wherein one web extends to form a rear fin extending in the
material flow direction. In addition, the mixer has at least two
forward angled surfaces and two rear angled surfaces that are
connected by the two planar webs. The webs are positioned so they
do not intersect the central, longitudinal axis of the conduit and
combine with the interior walls to form two, asymmetrical, lateral
passageways of varying flow area.
[0011] In still another aspect, the invention provides a method for
mixing at least two materials where a stream of material is ejected
into a conduit and dividing the stream into a plurality of parts
using baffles having a length to width ratio of 1.0 to 1.6.
[0012] There has thus been outlined, rather broadly, the more
important features of the invention in order that the detailed
description thereof that follows may be better understood, and in
order that the present contribution to the art may be better
appreciated. There are, of course, additional features of the
invention that will be described below and which will form the
subject matter of the claims appended hereto.
[0013] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of other embodiments and of being practiced
and carried out in various ways. Also, it is to be understood that
the phraseology and terminology employed herein, as well as the
abstract included below, are for the purpose of description and
should not be regarded as limiting.
[0014] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates a preferred embodiment of a twenty-four
stage mixer in accordance with a preferred embodiment of the
invention.
[0016] FIG. 2 is an isometric view of interconnected baffles
overlapping in a chain.
[0017] FIG. 3 is an isometric view of a 90.degree. right-handed
baffle employed in the mixer of FIG. 2.
[0018] FIG. 4 is an isometric view of a 90.degree. left-handed
baffle employed in the mixer of FIG. 2.
[0019] FIG. 5 is an isometric view of a 270.degree. supplemental
baffle.
[0020] FIG. 6 is a schematic representation of the progressive
stages of division, expansion and recombination that may occur to
the materials flowing through the mixer containing only 90.degree.
baffles.
[0021] FIG. 7 is a schematic representation of the progressive
stages of division, expansion and recombination that may occur to
the materials flowing through the mixer containing both 90.degree.
baffles and 270.degree. baffles.
[0022] FIG. 8 shows a series of interconnected baffles in
accordance with an embodiment of the present invention and adapted
to be employed within a generally hexagonal conduit.
[0023] FIG. 9 is a cross-sectional end view of FIG. 8 showing the
flow paths of the present invention, taken through line 9-9 in FIG.
8.
[0024] FIG. 10 is an isometric view of the baffle arrangement in an
alternative embodiment wherein the webs of the baffles are
staggered.
[0025] FIG. 11 is a side view of the embodiment of FIG. 10.
[0026] FIG. 12 is a cross-sectional end view of the embodiment of
FIG. 10 showing the flow areas resulting from the staggered
baffles, taken through line 12-12 in FIG. 1.
[0027] FIG. 13 shows an alternative embodiment of the present
invention wherein the baffle surfaces are curved.
[0028] FIG. 14 is a side view of the embodiment of FIG. 13.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0029] Referring now to the figures wherein like reference numerals
indicate like elements, FIGS. 1-14 illustrate a presently preferred
embodiment of a static mixer. While in the embodiment depicted, the
mixer is used for the mixing of high viscosity liquids, it should
be understood that the present invention is not limited in its
application high viscosity liquids, and that it may be used to mix
other suitable materials.
[0030] As shown in FIGS. 1-4, the static mixer 10 of the present
invention comprises a conduit 12, an inlet 14, outlet 16 and a
series of alternating left-handed baffles 18 and right-handed
baffles 20. Two supplemental baffles 21 are also shown. FIG. 1
illustrates a twenty-four stage mixer having twenty-four baffles,
indicated by the numbers 18, 20, and 21. There are eleven
right-handed baffles 20, eleven left-handed baffles 20, and two
supplemental baffles 21. The baffles 18, 20, 21 are positioned in
the conduit 12, which has interior walls 13 and a central,
longitudinal axis X along which the materials flow in a flow
direction F. The baffles 18, 20 are mirror images of one another
wherein one is designated as a left-handed baffle 18 and the other
as a right-handed baffle 20. The baffles 18, 20 are provided with
two forward, angled surfaces 22 and two rear, angled surfaces 23
(the lower surfaces are not visible in the views). The front angled
surfaces 22 and rear angled surfaces 23 are connected by two planar
webs 24, 27 that intersect one another. In the preferred
embodiment, the baffles are formed as an integral string. The
string has a pair of opposing side walls 15 (shown in FIG. 1),
which slide within opposed walls 13 of the conduit and provide
support and rigidity during insertion and operation. FIG. 2
illustrates a series of interconnected left-handed and right-handed
baffles 18, 20 with a square cross-section that have been removed
from the conduit 12 shown in FIG. 1.
[0031] FIG. 3 is a detailed view of a baffle designated as a
right-handed baffle 20. The baffle 20 is provided with a first,
generally planar web 24 that has opposing sides 24a and 24b and a
second, 5 generally planar web 27 having opposing sides 27a and
27b. The webs 24 extend generally parallel to the flow direction
and intersect one another. The baffle 20 is also provided with
first, forward surface 22 wherein the surface 22 is perpendicular
to one side of the web 24a and at an angle to a plane that is
perpendicular to the material flow. A second, forward surface is
shown in FIG. 2 wherein the surface 22 is perpendicular to the
other side of the web 24b and at an angle to a plane that is
perpendicular to the material flow. FIG. 2 also shows a first, rear
surface 23 wherein the surface is perpendicular to one side of the
web 27b and at an angle to a plane that is perpendicular to the
material flow. The baffle 20 also has a second, rear surface 23.
The second, rear surface is perpendicular to the other side of the
27a and at an angle to a plane that is perpendicular to the
material flow. In addition, one of the webs 24, 27 extends past the
rear angled surfaces 23 to form a rear fin 25 that extends in the
flow direction.
[0032] FIG. 4 is a detailed view of a baffle designated as a
left-handed baffle 18. The left-hand baffle 18 is formed as a
mirror image of the right-hand baffle 20 shown in FIG. 3.
[0033] Embodiments of the invention can be constructed solely from
right-handed and left-handed baffles. However, in some instances,
the materials and/or fluid being passed through the mixer of the
present invention, tend to "channel" along the peripheral walls 13
of the conduit 12 and/or side walls 15 of the string of baffles,
creating the possibility for incomplete mixing. This channeling can
be reduced by placing supplemental baffles 21 to enhance radial
movement along the flow path. Radial movement is defined as
movement of the cross-sectional exterior streams (material
traveling along the periphery of the conduit) into the center of
the mixer 10 and conversely, movement of the interior streams out
to the peripheral walls of the conduit 12. Therefore, in the
preferred embodiment, a supplemental baffle 21, as depicted in FIG.
5, is utilized to enhance radial movement along the flow path.
[0034] As shown in FIG. 5, the supplemental baffle 21 is provided
with six (6) forward and rear surfaces, 22 and 23 respectively,
along with four (4) planar webs 24, 27, 31, 33 that extend between
the forward and rear surfaces. The first and second planar webs 24,
27, each extend parallel to the flow direction and intersect one
another while the six forward surfaces and the six rear surfaces
22, 23, are all angled relative to a plane that is perpendicular to
the flow direction of the mixer. The first, forward surface 22 is
perpendicular to one side of the first web 24a while the second,
forward surface 22 is perpendicular to the other side of the web
24b. The first, rear surface 23 is perpendicular to one side of the
second web 27b while the second rear surface is perpendicular to
the other side of the web 27a. The supplemental baffle 21 has a
third, planar web that intersects the second planar web 24 and is
similar to the first and second planar webs in that it has opposing
sides and extends parallel to the flow direction. The third,
forward surface 22 is perpendicular to one side of the second web
27a while the fourth, forward surface 22 (not shown) is
perpendicular to the other side of the second web 27b. The fifth,
forward surface 22 is perpendicular to one side of the third web 31
a while the sixth, forward surface 22 is perpendicular to the other
side of the third web 31b. The fourth, planar web 33 of the
supplemental baffle 21 intersects the third planar web 31 and is
similar to the first, second and third planar webs in that it has
opposing sides and extends parallel to the flow direction. In
addition, the fourth, planar web 33 forms a rear fin 25 extending
in the flow direction. The third rear surface 23 is perpendicular
to the third, planar web 31 a while the fourth, rear surface is
perpendicular to the other side of the third web 31b. The fifth,
rear surface 23 is perpendicular one side of the fourth, planar web
33a while the sixth, rear surface is perpendicular the other side
of the fourth planar web 33b. Although the angled surfaces 22, 23
are described as perpendicular to the respective webs, it will be
appreciated that they are also angled relative to a plane that is
perpendicular to the flow direction and accordingly they are not
perpendicular to the flow direction.
[0035] FIG. 6 illustrates the various operations that occur when a
stream first passes over a right-handed 90.degree. baffle 30 and
then proceeds to pass over a left-handed 90.degree. baffle in
accordance with the present invention. In this illustration, the
main stream 29 is composed two smaller streams 26, 28. Initially,
the main stream 29 is divided into two sections designated by 32
and 34. In stage 36, the cross-sectional area of the streams 26, 28
is reduced without significantly rotating the flow laminae. This
reduction is due to a change in flow area that occurs where the
baffles are occupying a portion of the constant cross-sectional
internal area of the conduit. The streams 32, 34 then proceed to
stage 38 where they are widened in a direction perpendicular to the
plane of division. The streams are then recombined before
proceeding to the next baffle 40. As a result, a stream as shown in
stage 29, after passing through a single baffle 30 in accordance
with the present invention, has been transferred from two layers to
four layers after passing over one baffle and transferred from four
to eight after passing over the second baffle.
[0036] As can be observed in FIG. 6, sub-stream 28 is spot marked
33 so the flow of the sub-stream 28 may be tracked as the main
stream 29 passes over two consecutive baffles 30 and 40
respectively. The mark 33 tends to stay on the bottom surface of
the conduit 12, displaying the channeling phenomenon previously
described. FIG. 7 illustrates the various operations that occur
when a stream passes over a supplemental baffle 21 in accordance
with the present invention. As illustrated in FIGS. 6 and 7, the
main stream 29 is composed of two smaller streams 26, 28 wherein
one of the smaller streams is spot marked 33. As it can be observed
by tracking the mark 33, the streams 26, 28 have a flow path
through the supplemental 21 baffle similar to the path through the
90.degree. baffles shown in FIG. 6. However, instead of remaining
on the lower surface of the conduit 12, the spot tends to work
upward or towards the radial center of the mixer upon entering
section 42 of the supplemental baffle 21. Thus, the supplemental
baffles 21 ensure that fluids channeling along the outside walls of
the conduit 12 are directed into the center of the mixer 10,
thereby allowing for more appropriate layering.
[0037] FIG. 8 is a detailed view of a series of interconnected
baffles 18, 20 in accordance with an alternative embodiment of the
present invention having a generally hexagonal cross-section and
adapted to be used within a generally hexagonal conduit. FIG. 9 is
an end view of the interconnected baffles shown in FIG. 8 showing
the cross-sectional area of the flow passages 48.
[0038] It is generally preferred, that the materials to be mixed,
should be supplied to the mixer 10 in equal proportions. However,
several factors contribute to the unequal proportions of materials.
These factors include but are not limited to differing viscosities,
pulsations of the supply pump and pre-flow and after-flow "drool"
of lower viscosity material. In cases such as these, asymmetrical
baffles, as depicted by A, B in FIGS. 10 and 11, may act to provide
a correcting factor to the unequal distribution of materials into
the mixer 10. The asymmetrical baffles result in asymmetrical flow
paths 50, 52, as show in FIG. 12, wherein the flow path designated
by the number 50 makes up 60% of the total flow area of the mixer
and the flow path designated by 52 makes up 40% of the total flow
area of the mixer. As a result of the staggered orientation of the
baffles, the distribution of the flow of materials through the
mixer is more even. The staggered combinations may consist of all
right-handed baffles at different orientations, all left-handed
baffles at different orientations, combinations of both and various
similar combinations depending upon the application. It will be
appreciated that in this embodiment the webs are offset from the
central longitudinal axis of the mixer. In FIGS. 13 and 14 there is
illustrated a series of interconnected baffles in accordance with
an alternative embodiment of the present invention wherein the
baffles 54 are provided with curved forward and rear surfaces, 56
and 58 respectively. The surfaces may be concave as depicted in
FIGS. 13 and 14 or convex, depending upon the application.
[0039] Although the apparatus has been described as having a flow
direction, this is merely for descriptive convenience. The mixer
can also be operated with an opposite direction of flow.
[0040] The above description and drawings are only illustrative of
preferred embodiments which achieve the objects, features, and
advantages of the present invention, and is not intended that the
present invention be limited thereto. Any modification of the
present invention which comes within the spirit and scope of the
following claims is considered to be part of the present
invention.
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